Alert archive / California / Mesoscale Discussions in 2014

Mesoscale Discussion 621

May 19, 2014Colusa County, Glenn County, Tehama County, California

The Storm Prediction Center issued this mesoscale discussion at May 19, 2014, 3:09 PM PDT for Colusa County, Glenn County, Tehama County, California. It was in force for 2 hr.

The area

The outline as issued.

The facts

Issued
May 19, 2014, 3:09 PM PDT (22:09 UTC)
Expired
May 19, 2014, 5:15 PM PDT
In force
2 hr
Issued by
the Storm Prediction Center
Chance of a watch
5%

Counties Colusa County, CA, Glenn County, CA, Tehama County, CA

The radar

The Beale AFB radar (KBBX), 77 km from the middle of the area, began a volume at 22:09 UTC, the scan nearest the moment this went out.

Open the radar archive at this moment

The archived warnings, watches and discussions in force at that minute are drawn over the scan, this one among them.

The nearest sounding before it

Oakland, CA (KOAK), launched 12:00Z, 10.2 hours before the alert went out and 246 km from the middle of its area. This is the routine balloon launch nearest before it, the air the forecaster had in hand, not a measurement taken for the alert.

Skew-T log-pSkew-T log-p diagram, Oakland, CA at 12:00Z on 2014-05-19Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 0 joules per kilogram.LCL10008507005003002001001 km2 km3 km6 km9 km12 km15 km-30°-20°-10°0°10°20°30°40°
Temperature in red, dew point in green, the mixed-layer parcel dashed.
HodographHodograph, Oakland, CA at 12:00Z on 2014-05-19The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity -21 square meters per square second.1939587897Sfc1 km3 km6 km9 kmRMLM
The wind turning with height, colored by layer: ground to 1 km, 1 to 3 km, 3 to 6 km, 6 to 10 km.
Mixed-layer CAPE
0 J/kg
Mixed-layer CIN
No buoyant parcel
Mixed-layer LCL
970 m above ground
0-6 km bulk shear
45 kt
0-1 km storm-relative helicity
-21 m²/s²
0-3 km storm-relative helicity
18 m²/s²
Significant tornado parameter
0.0
Supercell composite
0.0

Open this sounding in Storm Lab

The text

As transmitted, in the capitals the NWS used until 2016.

344 
ACUS11 KWNS 192209
SWOMCD
SPC MCD 192209 
CAZ000-200015-

MESOSCALE DISCUSSION 0621
NWS STORM PREDICTION CENTER NORMAN OK
0509 PM CDT MON MAY 19 2014

AREAS AFFECTED...NORTH CENTRAL CALIFORNIA

CONCERNING...SEVERE POTENTIAL...WATCH UNLIKELY 

VALID 192209Z - 200015Z

PROBABILITY OF WATCH ISSUANCE...5 PERCENT

SUMMARY...THUNDERSTORMS HAVE DEVELOPED OVER THE HIGHER TERRAIN TO
THE WEST OF THE SACRAMENTO VALLEY. THESE THUNDERSTORMS WILL BE
CAPABLE OF PRODUCING HAIL AND STRONG/GUSTY WINDS.

DISCUSSION...THUNDERSTORMS HAVE DEVELOPED OVER THE HIGHER TERRAIN TO
THE WEST OF THE SACRAMENTO VALLEY. THESE STORMS HAVE DEVELOPED IN AN
ENVIRONMENT CHARACTERIZED BY MUCAPE VALUES AROUND 1000 J/KG /PER
MODIFIED 21 UTC KRBL RAP SOUNDING/ AND WEAK DEEP-LAYER SHEAR /AT OR
BELOW 20 KTS/. THIS WOULD SUGGEST MULTI-CELLS TIED TO...OR JUST
DOWNSTREAM OF...THE TERRAIN WILL BE THE PRIMARY THUNDERSTORM MODE.

GIVEN THE DEGREE OF INSTABILITY...AND THE COLD AIR ALOFT ASSOCIATED
WITH THE CLOSED LOW TO THE WEST...SMALL HAIL /BRIEFLY APPROACHING 1
INCH/ AND STRONG/GUSTY WINDS /GENERALLY LESS THEN 60 MPH/ CAN BE
EXPECTED WITH THE STRONGEST CORES. THE BRIEF/ISOLATED NATURE OF ANY
SEVERE-CRITERIA EVENT SUGGESTS A WATCH WILL NOT BE NEEDED.

..MARSH/EDWARDS.. 05/19/2014

...PLEASE SEE WWW.SPC.NOAA.GOV FOR GRAPHIC PRODUCT...

ATTN...WFO...STO...

LAT...LON   40322278 40462270 40592226 40232195 39822176 39302164
            39022209 39372255 39972273 40322278

Nearby

Mesoscale Discussions in California, 2014Every mesoscale discussion in 2014

Sources

The product and its follow-ups from the Iowa Environmental Mesonet's archive of National Weather Service and Storm Prediction Center text; the sounding from the Mesonet's radiosonde archive; radar from the NEXRAD Level II archive.